
/**
 * Copyright 2009 cestum.org
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
package org.waveprotocol.wave.model.operation
{
import org.waveprotocol.wave.model.document.operation.DocumentOperation;
import org.waveprotocol.wave.model.document.operation.impl.DocumentOperationUtil;
import org.waveprotocol.wave.model.util.Preconditions;

public class SyntaticIdentity extends AbstractOpEquator
{
	public function SyntaticIdentity()
	{
		super();
	}
	override public function equal(a:DocumentOperation, b:DocumentOperation):Boolean {
		Preconditions.checkNotNull(a, "First argument is null");
		Preconditions.checkNotNull(b, "Second argument is null");
		return equalNullable(a, b);
	}
	
	
	override public function equalNullable(a:DocumentOperation, b:DocumentOperation):Boolean {
		if (a == null) {
			return b == null;
		}
		if (b == null) {
			return false;
		}
		// TODO: Comparing by stringifying is unnecessarily expensive.
		return DocumentOperationUtil.toConciseString(a) == (DocumentOperationUtil.toConciseString(b));
	}
}
}